High linearity fully-balanced mixer

Abstract

The invention discloses a high linearity fully-balanced mixer. The drain of a PMOS transistor PM1 and the drain of a PMOS transistor PM3 are connected to an input signal VRF+; the source of the PMOS transistor PM1 is connected to the source of the PMOS transistor PM4; the source of a PMOS transistor PM3 is connected to the source of a PMOS transistor PM2; the drain of the PMOS transistor PM2 and the drain of the PMOS transistor PM 4 are connected to an input signal VRF-; the gate of the PMOS transistor PM1 and the gate of the PMOS transistor PM2 are connected to a local oscillator signal VLO+; the gate of the PMOS transistor PM3 and the gate of the PMOS transistor PM4 are connected to a local oscillator signal VLO-; the source of the PMOS transistor PM1 is connected to the source of a PMOS transistor PM5; the source of the PMOS transistor PM5 is connected to the inverse input end of an operational amplifier; the drain of the PMOS transistor PM5 is connected to the positive direction input end of the operational amplifier; the gate of the PMOS transistor PM5 is grounded; the source of the PMOS transistor PM2 is connected to the source of a PMOS transistor PM6; the source of the PMOS transistor PM6 is connected to the in-phase input end of the operational amplifier; the drain of the PMOS transistor PM6 is connected to the negative direction output end of the operational amplifier; and the gate of the PMOS transistor PM6 is grounded. The invention is advantaged by improving the linearity of the mixer under low voltage.

Description

technical field [0001] The invention relates to the field of electronic circuits, in particular to a fully balanced mixer with high linearity. Background technique [0002] The mixer is a very important part of the radio frequency circuit. Its function is to realize the change of the signal carrier and generate a new frequency component different from the frequency of the input signal. In the receiver system, the mixer converts the RF signal down to an intermediate frequency signal for subsequent circuit processing; in the transmitter system, the mixer converts the intermediate frequency signal into an RF signal, which is amplified by the power amplifier and transmitted by the antenna. go out. The performance of the mixer will directly affect the overall performance of the RF front-end circuit. [0003] The core working principle of the mixer is to multiply two input signals in the time domain, and then output the sum or difference of the frequency of the two signals to ac...

AI Technical Summary

Problems solved by technology

However, from image 3 The circuit is easy to see that the Gilbert mixer stacks three MOS tubes to limit its operation at low voltage; in addition, compared with the passive mixer, the Gilbert mixer converts the input voltage into a current through a transconductance unit , causing the nonlinearity of the transconductance unit, so it will affect the overall linearity of the mixer, and its linearity is not as good as that of a passive mixer

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